The present invention concerns a heald frame for weaving looms characterized by an extremely simple structure, the asymmetrical configuration of which has proved to be surprisingly advantageous.
It is known that, in weaving looms, the problem arises of giving to the heald frames a structure adapted to guarantee, without any excessive weight, a rigid behavior of such frames in dynamic conditions. In substance, it is necessary to avoid, or anyhow reduce to a minimum, the relative strains which, in dynamic conditions, tend to arise between the heald slide bars forming each frame (generally, elongated extruded sections), so as to reduce the dynamic flexural component which causes the breaking of the yarn.
In the past, said problem has been solved by inserting an intermediate tie rod connecting the two heald slide bars of the frame, so as to keep the distance between them constant during the working of the loom, or by stiffening the structure of the frame through increase of the moment of inertia of the heald slide bars, or finally by using, to form the heald slide bars, special composite materials of high rigidity and low weight.
The first two of these solutions have proved to be very scarcely practical, particularly as they create undesired bulk, they can cause interference with the warp yarns, and they considerably increase the mass and thus the inertia of the heald frames, while the third one involves excessive costs, taking into account the specific field of application.